﻿using System;
using System.Text;
using System.Drawing.Drawing2D;
using System.Drawing;
using System.IO;
using System.Drawing.Imaging;

namespace msBsc.Cls
{
    public class ValidateCode
    {

        private string code;
        private const int ImageHeigth = 26;             //验证码图片的高度
        private const double ImageLengthBase = 16;    //验证码图片中每个字符的宽度
        private const int ImageLineNumber = 25;         //噪音线的数量
        private const int ImagePointNumber = 100;       //噪点的数量
        private int length;
        public static string VALIDATECODEKEY = "VDIKEY";       //此处用来保存验证码到Session的Key的名称


        //设置验证码的长度和内容
        public ValidateCode()
        {
            this.length = 4;
            this.code = string.Empty;
        }

        /// <summary>
        /// 产生随机的验证码 
        /// </summary>
        /// <param name="length">验证码长度</param>
        /// <returns></returns>
        public string CreateCode(int length)
        {
            if (length <= 0)
            {
                length = this.length;
            }
            this.length = length;
            Random random = new Random();
            StringBuilder builder = new StringBuilder();
            //产生随机的验证码并拼接起来
            for (int i = 0; i < length; i++)
            {
                builder.Append(random.Next(0, 10));
            }
            this.code = builder.ToString();
            //this.Session[VALIDATECODEKEY] = this.code;
            return this.code;
        }

        /// <summary>
        /// 根据长度产生验证码
        /// 并将验证码画成图片
        /// </summary>
        /// <param name="length">验证码长度</param>
        public void CreateValidateImage(int length)
        {
            this.code = this.CreateCode(length);
            this.CreateValidateImage(this.code);
        }
        /// <summary>
        /// 根据产生的验证码生成图片
        /// </summary>
        /// <param name="code">验证码</param>
        public byte[] CreateValidateImage()
        {
            return CreateValidateImage(this.code);
        }
        /// <summary>
        /// 根据产生的验证码生成图片
        /// </summary>
        /// <param name="code">验证码</param>
        public byte[] CreateValidateImage(string code)
        {
            if (!string.IsNullOrEmpty(code))
            {
                //this.Session[VALIDATECODEKEY] = code;
                //初始化位图Bitmap对象，指定图片对象的大小(宽,高)
                using (Bitmap image = new Bitmap((int)Math.Ceiling((double)(code.Length * ImageLengthBase)), ImageHeigth))
                {
                    //初始化一块画布
                    Graphics graphics = Graphics.FromImage(image);
                    Random random = new Random();
                    try
                    {
                        int num5;
                        graphics.Clear(Color.White);
                        //绘制噪音线
                        for (num5 = 0; num5 < ImageLineNumber; num5++)
                        {
                            int num = random.Next(image.Width);
                            int num3 = random.Next(image.Height);
                            int num2 = random.Next(image.Width);
                            int num4 = random.Next(image.Height);
                            graphics.DrawLine(new Pen(Color.Silver), num, num3, num2, num4);
                        }
                        //验证码字体样式
                        Font font = new Font("Tahoma", 12, FontStyle.Italic | FontStyle.Bold);
                        LinearGradientBrush brush = new LinearGradientBrush(new Rectangle(0, 0, image.Width, image.Height), Color.Blue, Color.DarkRed, 1.2f, true);
                        //绘制验证码到画布
                        graphics.DrawString(code, font, brush, (float)2, (float)2);
                        //绘制噪点
                        for (num5 = 0; num5 < ImagePointNumber; num5++)
                        {
                            int x = random.Next(image.Width);
                            int y = random.Next(image.Height);
                            image.SetPixel(x, y, Color.FromArgb(random.Next()));
                        }
                        graphics.DrawRectangle(new Pen(Color.Silver), 0, 0, image.Width - 1, image.Height - 1);
                        using (MemoryStream stream = new MemoryStream())
                        {
                            //保存图片
                            image.Save(stream, ImageFormat.Gif);
                            //base.Response.ClearContent();
                            //base.Response.ContentType = "image/Gif";
                            //base.Response.BinaryWrite(stream.ToArray());
                            return stream.ToArray();
                        }
                    }
                    finally
                    {
                        graphics.Dispose();
                        image.Dispose();
                    }
                }
            }
            return null;
        }
        // Properties
        public string Code
        {
            get
            {
                return this.Code;
            }
        }
        public int Length
        {
            get
            {
                return this.length;
            }
            set
            {
                this.length = value;
            }
        }
    }




}